Muscle pain induced by static contraction is modulated by transient receptor potential vanilloid 1 and ankyrin 1 receptors

Abstract Molecular mechanisms involved in the development of muscle pain induced by static contraction are not completely elucidated. This study aimed to evaluate the involvement of the transient receptor potential vanilloid 1 (TRPV1) and the transient receptor potential ankyrin 1 (TRPA1) receptors expressed in peripheral and central terminals of primary afferents projected to gastrocnemius muscle and spinal cord in muscle pain induced by static contraction. An electrical stimulator provided the contraction of rat gastrocnemius muscle and mechanical muscle hyperalgesia was quantified through the pressure analgesimeter Randall-Selitto. AMG9810 and HC030031 were used. When administered in ipsilateral, but not contralateral gastrocnemius muscle, drugs prevented mechanical muscle hyperalgesia induced by static contraction. Similar results were obtained by intrathecal administrations. We propose that, in an inflammatory muscle pain, peripheral and central TRPV1 and TRPA1 work together to sensitize nociceptive afferent fibers, and that TRPV1 and TRPA1 receptors are potential target to control inflammatory muscle pain.

Miopatía por estatinas y vitamina D / Statin-Related Myopathy and Vitamin D

Las estatinas son fármacos habitualmente seguros y bien tolerados, muy eficaces para la prevención de trastornos cardiovasculares. La presencia de mialgias, poco frecuente, pero con incidencia dispar en diversos reportes, es una de las causas de abandono de su uso. También las distintas denominaciones (mialgia, miopatía, rabdomiólisis) y la subjetividad de cada paciente para referirlas han creado confusión en el tema. Se ha comenzado a reportar asociación entre niveles de vitamina D sérica disminuida y mayor riesgo de miopatía, por un lado, y trabajos donde pacientes que las abandonaban a causa de mialgias, con deficiencia de vitamina D, pueden tolerarlas una vez que se suplementa la vitamina hasta valores deseables. La presencia de polimorfismos en genes de enzimas que metabolizan o transportan a las estatinas es otro factor claramente relacionado con miopatía. Es posible que el déficit de vitamina D deba ser considerado un factor de riesgo para desarrollar miopatía por estatinas, como lo serían también la administración simultánea de fármacos que se metabolizan por la misma vía de citocromo P450, o la presencia de los polimorfismos mencionados. En conclusión, el hallazgo de tener deficiencia de vitamina D se asocia a miopatía por estatinas, o que es un factor de riego para desarrollarla, abre nuevas perspectivas para un gran número de pacientes que abandonan este tratamiento debido a esta patología. (AU)

Statins are usually safe and well tolerated drugs, very effective for preventing cardiovascular complications. The rare presence of myalgia, with different incidence as reported by several studies, is one of the causes of lack of drug compliance. Also the different symptoms referred (myalgia, myopathy, rhabdomyolysis) and the lack of objetivity of each patient when referring to the symptoms, have created confusion in this matter. Associations between decreased vitamin D levels and increased risk of myopathy has been reported. Indeed, studies describing patients with vitamin D deficiency who are not compliant due to myalgia show that they become tolerant to the drugs once the vitamin is supplemented to desirable values. The presence of gene polymorphisms for enzymes that metabolize or transport statins is another factor clearly related to myopathy. Therefore, we should consider vitamin D deficiency and other conditions such as the simultaneous administration of drugs that are metabolized by the same cytochrome P450 pathway, or the presence of mentioned polymorphisms as a risk factor for developing myopathy due to statins. In conclusion, the finding that vitamin D deficiency is associated with statin myopathy, or is a risk factor its develpoment, opens new perspectives for a large number of patients who leave this treatment due to this condition. (AU)

Prophylactic use of pregabalin for prevention of succinylcholine-induced fasciculation and myalgia: a randomized, double-blinded, placebo-controlled study / Uso profilático de pregabalina para prevenção de mialgia e fasciculação induzidas por succinilcolina: estudo randômico, duplo-cego e controlado por placebo

ABSTRACT BACKGROUND: Succinylcholine is commonly used to achieve profound neuromuscular blockade of rapid onset and short duration. OBJECTIVE: The present study compared the efficacy of pregabalin for prevention of succinylcholine-induced fasciculation and myalgia. DESIGN: Prospective, randomized, placebo controlled, double blinded study. MATERIALS AND METHODS: Patients of both genders undergoing elective spine surgery were randomly assigned to two groups. Patients in Group P (pregabalin group) received 150 mg of pregabalin orally 1 h prior to induction of anesthesia with sips of water and patients in Group C (control group) received placebo. Anesthesia was induced with fentanyl 1.5 mcg/kg, propofol 1.5-2.0 mg/kg followed by succinylcholine 1.5 mg/kg. The intensity of fasciculations was assessed by an observer blinded to the group allotment of the patient on a 4-point scale. A blinded observer recorded postoperative myalgia grade after 24 h of surgery. Patients were provided patient-controlled analgesia with fentanyl for postoperative pain relief. RESULTS: Demographic data of both groups were comparable (p > 0.05). The incidence of muscle fasciculation's was not significant between two groups (p = 0.707), while more patients in group C had moderate to severe fasciculation's compared to group P (p = 0.028). The incidence and severity of myalgia were significantly lower in group P (p < 0.05). CONCLUSION: Pregabalin 150 mg prevents succinylcholine-induced fasciculations and myalgia and also decreases the fentanyl consumption in elective sine surgery.

RESUMO JUSTIFICATIVA: A succinilcolina é comumente usada para atingir um bloqueio neuromuscular profundo, de início rápido e de curta duração. OBJETIVO: Comparar a eficácia de pregabalina na prevenção de mialgia e fasciculação induzidas por succinilcolina. DESENHO: Estudo prospectivo, randômico, duplo-cego e controlado por placebo. MATERIAIS E MÉTODOS: Pacientes de ambos os sexos submetidos a cirurgia eletiva de coluna foram aleatoriamente divididos em dois grupos. Os pacientes do Grupo P (pregabalina) receberam 150 mg de pregabalina oral uma hora antes da indução da anestesia e os pacientes do Grupo C (controle) receberam placebo. A anestesia foi induzida com fentanil (1,5 mcg/kg) e propofol (1,5-2,0 mg/kg), seguidos de succinilcolina 1,5 mg/kg. A intensidade da fasciculação foi avaliada por um observador, cego para a alocação dos grupos, com uma escala de 4 pontos. Um observador cego registrou o grau pós-operatório de mialgia após 24 horas de cirurgia. Para o alívio da dor no pós-operatório, fentanil foi usado em sistema de analgesia controlada pelo paciente. RESULTADOS: Os dados demográficos de ambos os grupos eram comparáveis (p > 0,05). A incidência de fasciculação muscular não foi significativa entre os dois grupos (p = 0,707), enquanto mais pacientes do Grupo C apresentaram fasciculação de moderada a grave em relação ao Grupo P (p = 0,028). A incidência e a gravidade da mialgia foram significativamente menores no grupo P (p < 0,05). CONCLUSÃO: Pregabalina (150 mg) previne mialgia e fasciculação induzidas por succinilcolina, além de diminur o consumo de fentanil em cirurgia eletiva de coluna.

Sustained increase of serum creatine phosphokinase levels and progressive muscle abnormalities associated with raltegravir use during a 32-week follow-up in an HIV-1 experienced patient on simplified HAART regimen, intolerant to protease inhibitors and abacavir: a case report / Aumento sostenido de los niveles de creatina fosfoquinasa sérica y las anormalidades musculares progresivas asociadas con el uso de raltegravir durante un seguimiento de 32 semanas en un paciente de VIH-1 experimentado en régimen de terapia TAAA simplificada, con intolerancia a los inhibidores de proteasa y abacavir: un reporte de caso

Sustained increase of serum creatine phosphokinase (CPK) concentrations and muscle abnormalities have been reported in patients taking raltegravir (RAL). In this report, we describe a case of sustained and asymptomatic increase of serum CPK concentrations associated with raltegravir, zidovudine, and lamivudine in an HIV-1 experienced patient with intolerance to protease inhibitor, abacavir and pencillin during 32 weeks of continuous drug monitoring.

Un aumento sostenido de las concentraciones de creatina fosfoquinasa sérica (CPK) y las anormalidades musculares ha sido reportado en relación con pacientes que toman raltegravir (RAL). En este reporte, describimos un caso de aumento sostenido y asintomático de concentraciones séricas de CPK asociadas con raltegravir, zidovudina y lamivudina en un paciente experimentado de VIH-1 con intolerancia al inhibidor de la proteasa, al abacavir y la penicilina durante 32 semanas de monitoreo farmacológico continuo.